Running biomechanics

for physiotherapy & sports medicine student & speakers...

1. Kinetic & Kinematics Of Running Dr. Nigam Prasad Dash MPT

2. Running is similar to walking in terms of locomotor activity. Running requires : 1. Greater balance – double float period 2. M uscle strength – elevation of HAT 3. J oint ROM - absorb increased energy to control weight During running gait cycle, the GRF & COP increase to 250 % of body weight (Double that of Walking).

3. Difference b et n Running & Walking Time & ground contact pattern. Greater joint motion & eccentric muscle work. Double & single limb support (period of double limb float). < 40% of stance & > 60% swing (vice versa) Running – speed Stance time Swing time For Running – 1 st increase in step length 2 nd step rate.

4. Float period (phase) Biomechanical feature which distinguishes running from walking. Time spends in float LEADS TO increase in running speed. This phase starts from ipsilateral toe off. For this in running stance phase equates 40% & swing phase 60%.

5. Gait Cycle Of Running Gait cycle begins when one foot comes in contact with the ground and ends when the same foot contacts the ground again. 2 phases – Stance & Swing phase Initial swing Loading(heel strike to foot flat) Terminal swing Mid stance (foot flat to heel off) ( forward descent ) Propulsion(heel off to toe off)

6. Loading(heel strike to foot flat) Progression towards heel strike Foot supinated with slight inversion(0-5*) Pelvis ant tilt & internal rot (10 *) Hip external rot(10*) & flexed(20-30*) Knee flex (10*) Due to lateral directed GRF,Cascade of event (foot eversion, hip internal rot & adduction,knee flexion(45*)) This help GRF pass post to the knee joint. These all done by gluteus eccentric contraction for dissipate of GRF.

7. Rear foot eversion gives more alignment to mid tarsal joints (unlocking). This mechanism allows the forefoot to make solid contact with ground at foot flat.

8. Midstace (foot flat to heel off) Fore foot making contact with ground. Biomechanical function involves shock absorption following loading to prepare for propulsion. During this time ankle moves towards maximal dorsi flexion(20*). Same time hip & knee moving from flexion towards extension for assisting forward motion body COM. Max foot pronation followed by ankle dorsi flexion should reach, rear foot eversion( 10*)& fore foot abduction (5*) as the COM passed ant to the stance limb.

9. Propulsion(heel off to toe off) Following heel off foot continues to supinate & plantar flexed. rear foot invertion transverse tarsal joint converge mid foot locked ( creats rigid lever) Then stance limb goes for externally rotation & excessive extention & knee flexion.(hamstring contraction) Acceleration of stance limb starts by maintaining same rigid liver i.e by (contraction of gastrocnemius, soleous , tibialis post & foot intrinsic)

10. Windlass mechanism helps in giving passive rigidity to foot.

11. Initial Swing After toe off the body thrust into the 1 st FLOAT phase. (rectus femoris & iliopsoas contracts for forward momentum of swing limb) Then preparation for terminal swing starts by ( tibialis ant, hip adductors eccentrically) At this time swing side relies on contralateral gluteal musculature to dissipate the GRF produced by this event & prevent pelvic dropping in swing side.

12. Terminal swing Following contralateral toe off the body is thrust into the 2 nd FLOAT phase. During this time swing hip reaches maximal flexion (30*) (before coming under control of hams & gluts) Same hams activity slows the rapid extension of knee for preparation of heel strike & hip adductors control eccentrically to control abduction. Then adductors acts concentrically to bring hip towards midline.

13. Kinematics Of Running Sagittal plane:- in this plane running exhibit out pelvic tilt & thigh angle. At initial contact - hip flexes 20-45* after which it goes for extension till toe off. At terminal swing hip flexion decreases that lead to reduction of velocity of the foot relative to the ground. In runners pelvic motion is minimized. (to conserve energy & efficiency)

14. Increase of lumber lordosis . (from mid stance to toe off & from mid swing to terminal swing) Because limitation of hip extensor mobility may place lumber spine in compromised position of excessive lordosis & also strain on hamstring muscle.(back pain)

15. At initial contact knee flexes 15-25*. at mid stance knee flexes 45*. at propulsion phase knee extends of 25*. but in swing phase knee reaches beyond 90* of flexion. At initial contact ankle in neutral. at midstance 20* of dorsiflexion as leg is loded . at toe off 15-35* of plantar flexion & that continues till preparation of heel strike.

16. At initial contact foot goes for supination followed by calcaneous invertion 4*. as the progression occurs subtalar joints pronates followed by hind foot eversion & tibial internal rotation. (during 1 st 20% of stance phase)

17. Frontal Plane:- In this plane hip is adducted 6-12* with respect to pelvis from initial contact to midstance . Then from mid stance to mid swing hip abducts 6* to forward progression of body & clearance of swing leg. In terminal swing hip returns to adduction for for preparation of initial contact.

18. Transverse plane:- Movement pattern in this plane imp for energy efficiency. At initial contact – pelvis exhibit 8* of forward rotation. hip external rotation of 10* (mid stance) then internal rot to neutral (toe off) Foot shows max external rotation in midswing of 15*.

19. Kinetics Of Running Ankle, knee, hip power patterns are similar in running to those of walking, only the velocity influences the amplitude. When forward speed of runner increases, the peak GRF and rate of loading increases. During running sharp GRF at initial contact resulting in an impact peak. (depends on foot strike pattern) After initial peak GRF reaches 2.2 to 2.6 times of body weight in runners. During mid stance GRFs are highest on body.

20. Anteroposterior GRF can alter through strike style(fore foot & heel), cadence & running surface(downhill & uphill).

21. THANK YOU…